Vitamin B12 Deficiency: Signs, Causes and Food Sources

November 8, 2026

by admin

Vitamin B12 helps make red blood cells and keeps nerves healthy, and a shortage can cause tiredness, tingling in the hands and feet, and memory or mood changes. It is found mainly in animal foods, so vegetarians, vegans and older adults, and people with certain stomach conditions or medicines, are more likely to run low.

QUICK ANSWERIf you often feel tired or weak, have numbness or tingling, or are at higher risk, ask your doctor for a B12 blood test. Treatment with supplements or injections works well, and starting early protects the nerves.

2.4 mcg

Recommended daily B12 for most adults

Animal foods

Main natural source of B12

Blood test

Confirms low B12 levels

Nerves

Damage can become permanent if untreated

What Does Vitamin B12 Do?

Vitamin B12 is needed to make red blood cells, build DNA and keep the nerves working. Without enough, the body can develop a type of anaemia and nerve problems. The body stores B12 in the liver for years, so deficiency often develops slowly.

Common Signs of Low B12

ENERGYTiredness and weaknessFeeling worn out even after rest.

SKINPale or yellowish skinA sign of anaemia.

NERVESTingling or numbnessPins and needles in the hands and feet, or balance problems.

MOUTHSore, smooth tongueMouth ulcers or a red, sore tongue.

MINDMemory and mood changesPoor concentration, low mood or irritability.

Tiredness has many causes, including low vitamin D and an underactive thyroid; see vitamin D deficiency signs and causes and why hypothyroidism causes fatigue.

Who Is More at Risk?

DIET AND AGE

People who follow a vegan diet or eat little meat, fish, eggs or dairy
Older adults, who absorb B12 less well

HEALTH AND MEDICINES

Pernicious anaemia, Crohn’s disease or coeliac disease
Weight-loss or stomach surgery
Long-term use of metformin or acid-reducing medicines

Food Sources of B12

EATMeat, fish and eggsNatural sources of B12.

DAIRYMilk, yoghurt and cheeseGood sources if you eat dairy.

FORTIFIEDFortified foodsSome cereals and plant milks have B12 added; check the label.

Testing and Treatment

A simple blood test shows your B12 level, and your doctor may check for related causes. Treatment depends on the cause and may be B12 tablets or injections. Do not start high-dose supplements without advice, because symptoms like tingling can also come from other conditions that need different treatment.

SEE A DOCTOR IF

You have numbness, tingling or trouble walking or balancing
You have memory problems or confusion
You are very tired, breathless or look pale

Have questions about supplements?

Talk to a pharmacist before starting any vitamin or medicine.

Frequently Asked Questions

Can vegans get enough B12?

Only from fortified foods or supplements, so vegans are advised to use them regularly.

Can you take too much B12?

B12 has a low risk of toxicity, but you should still follow your doctor’s advice on dose and form.

How long does recovery take?

Energy often improves within weeks, but nerve symptoms can take months and may not fully recover if treatment is delayed.